Insulation stripper and wire separator for twisted wire pairs

ABSTRACT

Apparatus for untwisting and stripping the ends of wires in a twisted pair comprise a first clamp which clamps the pair and a pair of cooperable insulation cutting blades which serve as a second clamp. Twisted pair is engaged by clamps and second clamp is rotated in untwisting direction. After untwisting, wires are pulled from second clamp to strip insulation.

United States Patent [191 Folkenroth et a1.

INSULATION STRIPPER AND WIRE SEPARATOR FOR TWISTED WIRE PAIRS EarlEarnest Folkenroth; Robert Ullman, both of Harrisburg, Pa.

Assignee: AMP Incorporated, Harrisburg, Pa.

Filed: Apr. 11, 1974 Appl. No.: 459,982

Related US. Application Data Division ofServ N0v 258,334, May 31, 1972.

Inventors:

US. Cl. 140/149, 81/951 Int. Cl B2lf 21/00 Field of Search 140/1, 149;81/951 References Cited UNITED STATES PATENTS 7/1929 Hartman 8l/9.51

[111 3,853,156 Dec. 10, 1974 1,844,766 2/1932 Keller 8l/9.5l 2,915,92812/1959 Felts et a1... 81/951 3,003,375 10/1961 Hopkins 81/9.5l3,779,290 12/1973 Rich et a1. 140/149 Primary Examiner-Lowell A. LarsonAttorney, Agent, or FirmFrederick W. Raring; Jay L. Seitchik; William J.Keating [57] ABSTRACT Apparatus for untwisting and stripping the ends ofwires in a twisted pair comprise a first clamp which clamps the pair anda pair of cooperable insulation cutting blades which serve as a secondclamp. Twisted pair is engaged by clamps and second clamp is rotated inuntwisting direction. After untwisting, wires are pulled from secondclamp to strip insulation.

7 Claims, 19 Drawing Figures PAIENTED M1 3.853356 saw QMHZ.

PATENTEL DEC 1 0 I974 SHEET 05 U? 12 PATENTEL EEC] 01974 SHEET 05 HF 12PATENIEL DEC 1 OIQH sum '09 HF 12 PATENTEB U53 1 0 74 SHEH 11 Bf 12PATENIEU use 1 01974 SHEEI 512 M12 INSULATION STRIPPER AND WIRESEPARATOR FOR TWISTED WIRE PAIRS BACKGROUND OF THE INVENTION twistedtogether in a harness, rather than separately incorporated into theharness, a more compact and neater wiring harness is achieved and thetracing and identification of the wires is simplified.

The present invention is directed to the achievement of an improvedapparatus which is capable of simultaneously untwisting the wires in apair and stripping the insulation from each wire in a twisted wire pair;Such insulation stripping and pair untwisting operations must be carriedout repeatedly in any harness making or wiring operation where twistedwire pairs are used. In the past, it has been common practice to preparethe ends of the wires of a twisted pair for termination by manuallyuntwisting the wires and then individually stripping insulation from theend of each wire Itis accordingly an object of the invention to providean improved wire untwisting apparatus. A still further object is toprovide an apparatus capable of untwisting the wires of a twisted pair,stripping insulation from the end of each wire of the pair, andseparating the two wires so that they can be individually terminated orconnected in a circuit.

These and other objects of the invention are achieved in a preferredembodiment of the invention comprising a pair of insulation strippingblades which are movable relatively towards and away from each otheralong a predetermined path which is at least substantially rectilinear.When the blades are closed, they cut through the insulation of the wiresand in their closed condition, they serve as a clamp for the pair ofwires. The untwisting mechanism includes an additional clamp whichgrasps the wires adjacent to the stripping blades. Mechanism is providedfor rotating the blades relative to the clamp to untwist the wires.After untwisting, the wires are moved axially from between the blades tostrip the insulation from the wire ends.

In the drawing:

FIG. 1 is a perspective view of a twisted pair insulation strippingapparatus in accordance with the invention.

FIG. 1A is a perspective view of a short section of a twisted wire pair.

FIG. 2 is a view taken along the lines 2-2 of FIG. 1, this view showingthe positions of the parts on the insulation stripping blades are intheir opened or separated positions.

- FIG. 3 is a view similar to FIG. 2 but showing the insulationstripping blades in their closed positions.

FIG. 4 is a view taken along the lines 4-'-4 of FIG. 1.

FIG. 5 is a fragmentary plan view, on an enlarged scale, of theinsulation stripping blades of the apparatus of FIG. 1, this viewshowing the blades and their fully open or separated positions.

FIGS. 6 and 7 are views similar to FIG. 5 illustrating the manner inwhich the blades close around the twisted wire pair and cut through theinsulation of wires of the pair.

FIG. 7A and 7B show alternative types of stripping blades in accordancewith the invention.

FIG. 8 is a top plan view, partially in section, of a preferred form ofapparatus for both stripping the end portions of the wires in a twistedpair and untwisting the wires at the end of the pair.

FIG. 9 is a side view looking in the direction of the arrows 99 of FIG.8 of the apparatus.

FIG. 10 is an enlarged sectional view of the stripping head of theapparatus of FIG. 8 showing the positions of the parts at anintermediate stage of the operating cycle.

FIG. 11 is a fragmentary view illustrating the removal of the strippedand untwisted pair from the apparatus at the conclusion of the operatingcycle.

FIGS. 12 and 13 are views taken along the lines l212 and 13-13 of FIG.8.

FIG. 14 is a perspective view showing the stripping and untwisting head,the camming ring which controls the stripping blades, and the drivetrain for the camming ring and the stripping head, this view showing thepositions of the parts at the beginning of the operating cycle.

FIGS. 15 and 16 are views similar to FIG. 14 but showing the positionsof the parts at different stages of the operating cycle.

THE EMBODIMENT OF FIGS. l7

Referring first to FIG. 1A, a conventional twisted pair 2 of insulatedconductors comprises two individual wires 4, 6 which are helicallyintertwined. Each wire has a central metallic core 5 and an insulatingsheath 7 as shown in FIG. 5. When the end of a twisted'wire pair is tobe electrically connected in a harness, or when terminals are to becrimped onto the ends of the wires, it is necessary to strip the endportions of each wire 4, 6, and usually, to separate the wires adjacentto the end of the pair.

In the description which follows, a relatively simple strippingapparatus for stripping insulation from the ends of the wires 4, 6 willfirst be described and there will then be described an apparatus forboth stripping the wire ends and simultaneously separating the two wiresat the end of the pair. The stripping blades and the stripping apparatusshown in the stripping and untwisting devicev of FIG. 8 is substantiallysimilar to the simple insulation stripping device of FIGS. l7. Undersome circumstances, it is necessary to only strip the insulation whilein some harness making operations, both the stripping and untwistingoperations are required.

Referring first to FIG. 5, one pair of insulation stripping blades 8, 8in accordance with the invention are in the form of flat relatively thinplate like members and are mounted for movement towards and away fromeach other along a straight line, or substantially straight line, path.The opposed ends 10,10 of the blades each have first cutting edges 12,12' which extend transversely of the path of movement of the blades andsecond cutting edges 14 which extend forwardly from the edges 12, 12'and slightly divergently with respect to the path of movement of theblades. For reasons which will become apparent as this descriptionproceeds, the included angle between the edges l2, l4 and 12', 14' is atleast slightly greater than 90 and no greater than about 120.

The cutting edge 12 merges with a leading end portion 16 of the blade 8that extends laterally to the side of the blade and the cutting edge 14merges with a leading end portion 18 which also extends transversely,the edge 14 and the end portion 18 defining a point of intersectionwhich is located, in the case of the blade 8, slightly to the right ofthe common center line of the two blades. The blade 8', the upper blade,is similar to the blade 8 but is formed in a lefthand sense so that itsleading end portion 18' is on the lefthand side of the center line andits leading end portion 16 is on the righthand side of the center line.

At the beginning of a wire stripping operation, the blades 8, 8' will bespaced apart as shown in FIG. 5 and the wire pair will be positionedbetween the blades. As

'the blades move relatively towards each other, the in- -tersectionpoints 20, 20 will each engage one of the wires of the pair, turn theportion of the wire pair which is between the blades such that a lineconnecting the centers of the two wires will be parallel to the cuttingedges 14, I4 and will be located mid-way between these cutting edges asshown in FIG. 7.

After the blades have moved to their fully closed positions, FIG. 7, thereoriented wire pair will be captured between the cutting edges 14, 14'and 12, 12 and these cutting edges will have penetrated the insulationof each wire as shown in FIG. 7. The twisted pair can then be pulledaxially from between the blades thereby to cause tearing of theinsulation in the plane defined by the cutting edges so that the severedsections of insulation will be held by the blades and the stripped wireends will be pulled from the blades. It will be apparent from FIG. 7that the blades 8, 8 must not move beyond their closed positions asshown in FIG. 7 if nicking or cutting of the strands of the conductingcores 5 of thewires is to be avoided. In order to prevent such cuttingof the strands, the leading end portions l4, l8 and 16, 18 of the bladesare carefully machined so that they will abutt each other and act aspositive stops to define the limits of movement of the blades.

It should be explained that the orientation of the pair will be randomat the beginning of the operating cycle and FIG. 5 shows mostundesirable orientation. If the pair is oriented such that one wire ison top of the other wire, or nearly so, the reorientation of the wiresas illustrated in FIG. 6 will not take place.

The reorientation of the wires as shown in FIG. 6 is affected by theintersections 20, 20 of the edges 14, 14 with the ends 18, 18' of theblades. It follows that these intersections 20, 20' must be spaced fromthe common center line of the two blades by a distance which is lessthan the diameter of one of the wires so that the intersections willengage the wires when the blades move towards each other.

It should also be noted that the successful practice of the inventionrequires the long cutting edges 14, 14' should extend in the generaldirection of the path of movement of the blades. The shorter or firstcutting edges 12, 12' are of lesser importance and may not be essentialfor successful insulation stripping under some circumstances asdescribed below.

It will be apparent from the foregoing that certain dimensions of theblades are important for successful practice of the inventionas is trueof all insulation stripping operations. Thus when the blades are closedas shown in FIG. 7, cutting edges 14, 14' are spaced apart by a distancesubstantially equal to, but no less than, the diameter of the insulatedcore of each wire of the pair. The cutting edges 12, 12 are spaced apartby a distance equal to twice the diameter of the core ofeach wire plustwice the thickness of the insulating sheath of each wire. Where theinsulation is of the commonly used plastic variety, such as vinyl, itwill tear during pulling of I the pair and be separated in those areasin which it is not cut through to the wire core 5. This technique ofpartial cutting coupled with tearing of the insulation is employed inmany known insulation stripping devices.

As noted previously, the included angle 14 should be in the range ofslightly greater than 90 to about 120. This angle is not critical butbest results will be achieved if an angle of optimum extent is shown. Ithas been found that good results will be achieved with an included angleof about 105, which is approximately the angle shown in the drawing. Ifthe included angle is about 105, and the proportions are those of thedrawing, the intersections 20, 20' will be properly located to engagethe wires.

Many desirable types of positive stops for the blades may be employed.In the embodiment of FIGS. l-7, the ends 18, 16, 16, 18' are carefullyground so that they will function as a stop to define the closedpositions of the blades. Alternatively, the leading ends of the bladescan be designed such that they will overlap when the blades are in theirclosed condition and a different type of stop than that shown can beused.

The insulation stripping blades described above are preferred under mostcircumstances, but the alternative blades shown in FIGS. 7A and 78 maybe used under some conditions. The blades 8a, 8 of this embodiment haveleading ends 18a, 18' which overlap when the blades are in the opencondition, FIG. 7A. These blades have cutting edges 14a, 14a as providedin the previously described embodiment, but the edges 16a, 16a are notground to cutting edges. It is desirable, when blades of the type shownin FIG. 7A are used, to provide stationary stops 9, 9', which functionto confine the twisted pair of wires.

In use, the twisted pair is located as shown in FIG. 7A and the'bladesare then moved to their closed position, FIG. 7B. During such movement,the edges 14a, 14a turn the pair and reorient it if necessary. When theblades are fully closed, the edges 14a, will have penetrated theinsulation as shown in FIG. 7 B and the insulation can be stripped bysimply pulling the wire pair from between the blades.

The embodiment shown in FIGS. 7A and 7B demonstrates that the cuttingedges 12, 12 of the previous embodiment are not essential, althoughthese shorter cutting edges are desirable under many circumstances. Thisembodiment also demonstrates that the pair can be reoriented by thecutting edges which extend obliquely of the blades the edges 14a, 14arather than along a path extending between a pair of open insulationstripping blades which are closed after the wire has been fed. Theoverlapping blades would provide a convenient means of confining thewire pair during the wire feeding operation.

Referring now to FIG. 1, a relatively simple apparatus for the strippingwire pairs comprises a frame plate having a laterally extending arm 22thereon and having a piston cylinder 24 secured thereto. The piston rod26 of the piston cylinder is pivotally connected to a lever 28 whichextends through an opening 30 in the frame arm 22. Arm 28 is pivoted ona bushing 32 extending a fixed plate 48 described below. On each side ofthis bushing, the arm has a pin-slot connection 34, 35, 34, 36' witheach of two generally U-shaped blade holders 38, see FIG. 4. The lowerblade holder comprises two spaced apart plates 40, 44 which are joinedat their lower ends by a spacer block 42. The side plates 40, 44 aredisposed generally against the opposite sides of the previouslyidentified bearing block 48 which is integral with, and extendslaterally from, the frame arm 22. The lower insulation stripping blade 8is fixed to the side plate 44 by means of fasteners 46. As shown in FIG.1, a vertical groove or channel 47 is provided in the block 48 whichreceives the blade 8 and portions of the plate 41 in order to guide theblade holder and the blade along a straight line path drawing movementtoward the upper blade holder. The upper blade holder 38 is similar tothe lower blade holder 38 and need not be described in detail. It willbe apparent from FIG. 4

that during outward movement of the piston rod 26, the lever 28 will bemoved through a counterclockwise arc as viewed in FIG. 4 about itspivotal axis 32 to move the two blade holders 38, 38 and the blades 8,8' towards each other. I

The previously identified bushing is mounted in the bearing block 48 andserves as a guide for the twisted pair which is inserted into thebushing from the left in FIG. 2. In the disclosed embodiment, a stop isprovided at 52 (FIG. 1) to gauge the amount of insulation stripped fromthe wire. This stop is integral with an arm mounted on side block 44 bya fastener as shown.

In the use of the apparatus of FIGS. 1-7, the operator merely insertsthe wire through the bushing 32 until the wires engage at stop 52.Thereafter, the operator actuates the cylinder 24 by means of a suitableswitch or valve (not specifically shown) to cause movement of the bladeholders and the blades towards each other until the blades are in theirclosed condition. The operator then pulls the wire leftwardly as viewedin FIG. 3 while the blades are closed.

THE EMBODIMENT OF FIGS. 8-16 FIGS. 8-16 show an apparatus whichincorporates twisting pair insulation stripping blades in accordancewith FIGS. l-7 in combination with means for untwisttion of the pairinto the opening 60, the pair is clamped by a clamping ram 64 which isslidably mounted in a laterally extending recess in block 59. This ramis mounted on the end of a piston rod 66 of a pneumatic piston cylinder68. The opening 60 has an offset surface 61 adjacent to the face plate62 and in alignment with the clamping ram 64 so that the inserted pairwill be clamped in a position such that it will extend centrally throughthe opening 60.

The stripping and untwisting head is mounted on, and keyed or otherwisesecured to, an enlarged diameter forward portion 72 of a hollowrotatable shaft 74 which extends rearwardly through a suitable bearing76 in a support boss 78 on the end of an arm 80 of the frame 56. Thehead 70 comprises a cylindrical body portion 82 having a circular faceplate 84 secured to its rightwardly facing side by fasteners as shown inFIG. 13. The body portion 82 has two diametrically opposed radiallyextending slots therein in which are contained blade holder blocks 86,86. Stripping blades 8, 8' which may be similar, or substantiallysimilar, to the blades shown in FIGS. 1-7, are secured to the blocks 86,86 so that when the blocks move inwardly toward the axis of the shaft74, the blades will be moved from their opened positions to their closedpositions. The body portion 82 also has radially extending slots (FIG.13) extending normally of the slots in which blade holder blocks arecontained. The slots 85 permit ejection of the sections of insulationremoved from the wire ends as will be described below.

The hollow shaft 74 is axially aligned with the opening 60 and the faceplate 84 is provided with a central opening 88 so that a wire insertedthrough the clamping block 59 will enter the shaft and be centrallylocated between the blades 8, 8'.

The blade holder blocks 86, 86' are moved relatively towards each otherfrom the position of FIG. 8 to the position of FIG. 10 by means of arms90, 90, the ends 92 of which are slotted for the reception of pins 94extending across recesses in the blocks 86, 86'. The body portion 82 ofthe head 70 has openings through which these arms extend. Arms 90, 90'are mounted in axially extending recesses 96 in the enlarged diameterportion 72 of shaft 74 by means of pivot pins 98, 98' and the arms arenormally biased to the position shown in FIG. 8 by springs 99 which bearagainst the arms intermediate their ends and against the floors of therecesses 96.

Arms 90, 90' are swung inwardly and towards each other to close thestripping blades by camming rollers 100, FIGS. 8 and 12 mounted on pins102 which extend across recesses 103 in a camming collar 104. Thiscamming collar is keyed as shown at 106 (FIG. 12), by an axiallyextending key to the enlarged diameter portion 72 of the shaft to thatthe collar will rotatewith the shaft and is permitted to move axially onthe shaft from the position of FIG. 8 to the position of FIG. 10 therebyto swing the arms inwardly. Axial sliding movement of the collar 104 isachieved by means of a lever 108 pivoted intermediate its ends at 110 tothe frame and having a pin slot connection 112 at its outer end with aclevis on the end of a piston rod 114 extending from a piston cylinder116 which is mounted on the side of the frame. The inner end of thelever 108, that is the end proximate to the collar 104 has an integralyoke 118, the ends of which are on opposite sides of the collar and onwhich there are mounted rollers 120. These rollers are received in acircumferential recess 122 in the collar, an arrangement which permitsrotation of the collar and which permits axial movement of the collar onthe shaft. It will be apparent from FIG. 8 that upon leftward movementof the piston rod 1 14, the lever 108 will be swung in a clockwisedirection and the collar will be moved rightwardly to the position ofFIG. 10.

.T he shaft 74 is rotated several turns during each operating cycle by agear train which includes a beveled pinion 126 having an integral hub128. This pinion is mounted on the projecting lefthand end portion ofthe shaft 74, the extreme end portion of the shaft being threaded asshown at 130 and a lock nut 124 being employed to maintain the pinion inplace. The pinion is keyed or otherwise secured to the shaft 74 forrotation therewith.

The pinion 126 meshes with a bevel gear 132 which is secured to a shaft134 for rotation therewith. Shaft 134 extends laterally and is supportedin a suitable bearing boss 136 integral with the frame 156. A pinion 138is fixed on the shaft 134 for rotation therewith between the bevel gear132 and the boss 136. Pinion 138 meshes with a gear section 140 which iskeyed or otherwise secured to a rotationally mounted stub shaft 142.Stub shaft 142 (FIG. 14) is suitable supported for a rotation in theframe immediately beneath the shaft 134.

which extends from one end of a pneumatic cylinder 154, the other end ofthis cylinder being pivotally anchored to the frame at 156 so that thepiston can swing about its pivotal anchor during movement of the pistonrod 148 as shown in FIGS. 8 and 15. It will be apparent that movement ofthe piston rod will cause rotation of the gear section 140 through partof a revolution, rotation of the shaft 134 and by virtue of the bevelgear and pinion 132, 126, rotation of the shaft 74.

It is desirable to provide gauging means to control the length strippedduring operation. In the disclosed embodiment, a gauging means isprovided in the form of a rod 158 which extends through the hollowcenter of the shaft 74 and the end of which is proximate to the blades8, 8'. Rod 158 is threaded at 160 in the vicinity of the lefthand end ofthe boss 78 and the inside of the shaft has complementary threads. Rod158 projects leftwardly beyond the end of the beveled pinion 126 and hasexposed threads adjacent to the end of the shaft 74. A lock nut isprovided; on these exposed threads to lock the rod 158 in apredetermined position.

When it is desired to change the position of the rod 158, to increase ordecrease the length of insulation removed, the lock nut 162 is loosenedand the rod 158 is turned in the appropriate direction by means of aknob 164. The position of the rod is thus adjusted by the action of thethreads 160 and after the rod is properly positioned, the lock nut 162is tightened against the end of the shaft 74.

OPERATION At the beginning of the operating cycle, the parts will be inthe positions of FIG. 8. The operator'first inserts the twisted pairthrough the openings 63, 60, and 88 until the end of the pair engagesrighthand end of the rod 158. The rearward side of the piston cylinder68 is then pressurized to drive the clamping ram 64 inwardly and clampthe pair against the surface 61. The righthand side of the pistoncylinder 116 is then pressurized to cause the lever 108 to swing througha clockwise arc and move the camming collar 104 from the position ofFIG. 8 to the position of FIG. 10. This movement of the camming collarcauses closing movement of the insulation stripping blades 8, 8' so thatthe pair will be captured in the plane of the stripping blades. Thepiston cylinder 154 is then pressurized to cause rotation of the gearsector 140 and by virtue of the gear train 138, 132, and 126, to causeseveral complete revolutions of the shaft 74. The untwisting headrotates with the shaft and the pair is untwisted along that portion ofits length extending between the clamping ram 64 and the strip pingblades 8, 8. It will be apparent that the head 70 should be rotated inthe direction of the lay or twist in the pair. The number of turns ofthe head 70 during each operating cycle should be equal to the number ofturns in the pair between the ram 64 and the blades 8, 8'. The positionof the coupling 150, 152 of the crank 144 to the piston rod 148 can beset to result in the desired number of turns.

After completion of the untwisting operation, pressure is relieved fromthe rearward side of the piston cylinder 68 to cause retraction of theram 64 and releases of the pair by this ram. While the blades 8, 8remain in their closed condition, the operator pulls the pair from thehead 70 to remove the insulation from the portions of the wires whichextend inwardly beyond the blades. This same pulling operation resultsin untwisting of the turns in the pair which are between the blades andthe ends of the wires.

Subsequently, the lefthand side of the piston cylinder 116 ispressurized to return the lever 88 to the position of FIG. 8 and therighthand side of the piston cylinder 154 is pressurized to return thegear section 140 to the position of FIG. 14. During the return of theseparts to their normal positions, the head 70 will be rotated in thedirection opposite to the direction it rotates during the untwistingoperation. During such rotation of the head, the segments of insulationwill be ejected through one of the slots under the influence ofcentrifugal force.

The foregoing description assumes that the piston cylinders 68, 116, and154 are double acting in which case suitable pneumatic controls can beprovided to pressurize the appropriate ends of the cylinders at theappropriate stages of the operating cycle. Alternatively, moresimplified controls can be used if these cylinders are single acting andhave internal springs to return their pistons to the starting positions.

It will be apparent from the foregoing description that the blades 8, 8'in the embodiment of FIG. 8 serve as clamps for the twisting pair afterthey have moved to their closed positions and during rotation of thehead 70. If it is desired to simply untwist the pair rather than toremove insulation, clamping plates can be substituted for the plates 8,8.

The head 70 rotates in the direction of the lay or twist of the pair asobserved from the vantage point of the face plate 84. The effect ofrotating the head 70 can also be achieved by rotating the clamping block59 in the direction of the lay of the pair or even by rotating both theclamping block and the head.

Other modifications within the scope of the appended claims will beapparent to those skilled in the means to cause movement thereof a shortdistance away from the stripping head at the conclusion of theuntwisting operation to pull the pair from between the insulationcutting blades and thereby spare the operator of this task.

What is claimed is: 1. Apparatus for untwisting the two wires of atwisted wire pair and substantially simultaneously stripping insulationfrom the end portions of said wires, said apparatus comprising:

first clamping means for clamping said twisted pair thereon againstrotation at a location remote from the'end of said pair, second clampingmeans for clamping said twisted pair thereon at a location adjacent saidend of said pair, said second clamping means comprising a pair ofopposed cutting blades which are movable relatively towards each otherinto surrounding relationship to said pair while cutting at leastpartially through the insulation of each wire of said pair, and meansfor rotating said clamping means relative to each other in oppositedirections about the axis of a twisted pair held in said clamping meanswhereby, upon clamping of said pair in said first and second clampingmeans with concomitant cutting of the insulation of said wires of saidpair by said second clamping means, and upon relative rotation of saidclamping means in the direction of the lay of said pair, said pair willbe untwisted between said first and second clamping means, and uponpulling of said pair from said second clamping means, the insulationwill be stripped from the end portions of said wires.

2. Apparatus as set forth in claim 1 wherein said means for rotatingsaid clamping means comprises means for rotating said second clampingmeans only.

3. Apparatus as set forth in claim 2 wherein said cutting blades aremounted in a head member, said head member being mounted on a shaft forrotation therewith, said means for rotating said clamping meanscomprising means for rotating said shaft.

4. Apparatus as set forth in claim 3 wherein said shaft is hollow and isadapted to receive end portions of said pair, and adjustable stop meansin said shaft adapted to be engaged by said pair to gauge the length ofinsulation stripped from said wires of said pair.

5. Apparatus for untwisting the two wires of a twisted wire pair andsubstantially simultaneously stripping insulation from the end portionsof said wires, said apparatus comprising:

a first clamping means for clamping said twisted pair against rotationat a location adjacent to the end of said pair,

an untwisting and stripping head, means for rotating said head in bothdirections about an axis extending centrally through said head andcoinciding with the axis of a twisted pair held in said first clampingmeans and extending towards said head,

a pair of insulation cutting blades in said head, said blades being onopposite sides of said axis, said blades being normally in an openposition relative to each other in which said blades are spaced apart,said blades being movable towards each other to a closed position, saidblades constituting a second clamping means,

said blades having leading ends which are opposed to each other,cooperable insulation cutting edges on said leading ends, said edgessurrounding said axis when said blades are in said closed position andpenetrating at least partially through the insulation of the two wiresof a twisted pair clamped in said first clamping means and extendingalong said axis towards, and into said head, and

blade moving means for moving said blades from said open position tosaid closed position, said blade moving means being effective tomaintain said blades in said closed position during rotation of saidhead whereby,

upon positioning said pair on said axis with its end portion extendingfrom said first clamping means past said blades, and upon movement ofsaid blades to said closed position, and upon rotation of said head inthe direction of the lay of said pair, the insulation of both wires ofsaid pair will be circumferentially cut by said cutting edges and saidpair will be untwisted between said head and said first clamping means,and upon pulling of said pair from between said blades, the insulationwill be removed from the portions of said wires which extend beyond saidblades.

6. Apparatus as set forth in claim 5 wherein said head is secured to ashaft in alignment with said axis, said means for rotating said headcomprising means for rotating said shaft.

7. Apparatus as set forth in claim 6 wherein said blade moving meanscomprises camming means on said shaft.

1. Apparatus for untwisting the two wires of a twisted wire pair andsubstantially simultaneously stripping insulation from the end portionsof said wires, said apparatus comprising: first clamping means forclamping said twisted pair thereon against rotation at a location remotefrom the end of said pair, second clamping means for clamping saidtwisted pair thereon at a location adjacent said end of said pair, saidsecond clamping means comprising a pair of opposed cutting blades whichare movable relatively towards each other into surrounding relationshipto said pair while cutting at least partially through the insulation ofeach wire of said pair, and means for rotating said clamping meansrelative to each other in opposite directions about the axis of atwisted pair held in said clamping means whereby, upon clamping of saidpair in said first and second clamping means with concomitant cutting ofthe insulation of said wires of said pair by said second clamping means,and upon relative rotation of said clamping means in the direction ofthe lay of said pair, said pair will be untwisted between said first andsecond clamping means, and upon pulling of said pair from said secondclamping means, the insulation will be stripped from the end portions ofsaid wires.
 2. Apparatus as set forth in claim 1 wherein said means forrotating said clamping means comprises means for rotating said secondclamping means only.
 3. Apparatus as set forth in claim 2 wherein saidcutting blades are mounted in a head member, said head member beingmounted on a shaft for rotation therewith, said means for rotating saidclamping means comprising means for rotating said shaft.
 4. Apparatus asset forth in claim 3 wherein said shaft is hollow and is adapted toreceive end portions of said pair, and adjustable stop means in saidshaft adapted to be engaged by said pair to gauge the length ofinsulation stripped from said wires of said pair.
 5. Apparatus foruntwisting the two wires of a twisted wire pair and substantiallysimultaneously stripping insulation from the end portions of said wires,said apparatus comprising: a first clamping means for clamping saidtwisted pair against rotation at a location adjacent to the end of saidpair, an untwisting and stripping head, means for rotating said head inboth directions about an axis extending centrally through said head andcoinciding with the axis of a twisted pair held in said first clampingmeans and extending towards said head, a pair of insulation cuttingblades in said head, said blades being on opposite sides of said axis,said blades being normally in an open position relative to each other inwhich said blades are spaced apart, Said blades being movable towardseach other to a closed position, said blades constituting a secondclamping means, said blades having leading ends which are opposed toeach other, cooperable insulation cutting edges on said leading ends,said edges surrounding said axis when said blades are in said closedposition and penetrating at least partially through the insulation ofthe two wires of a twisted pair clamped in said first clamping means andextending along said axis towards, and into said head, and blade movingmeans for moving said blades from said open position to said closedposition, said blade moving means being effective to maintain saidblades in said closed position during rotation of said head whereby,upon positioning said pair on said axis with its end portion extendingfrom said first clamping means past said blades, and upon movement ofsaid blades to said closed position, and upon rotation of said head inthe direction of the lay of said pair, the insulation of both wires ofsaid pair will be circumferentially cut by said cutting edges and saidpair will be untwisted between said head and said first clamping means,and upon pulling of said pair from between said blades, the insulationwill be removed from the portions of said wires which extend beyond saidblades.
 6. Apparatus as set forth in claim 5 wherein said head issecured to a shaft in alignment with said axis, said means for rotatingsaid head comprising means for rotating said shaft.
 7. Apparatus as setforth in claim 6 wherein said blade moving means comprises camming meanson said shaft.